Tilapia are considered to be relatively resistant to many of the common diseases that beset other farmed fish. Viral diseases, however, are not common, and there are only a few reports in the literature.
Syncytial Hepatitis of Tilapia (SHT) is a newly described viral disease reported from several countries where tilapia farming is present. This virus is a member of the Orthomyxoviridae family. It has been demonstrated within hepatocytes of affected fish.
The described ultrastructural changes provide further evidence to support the previous suggestion of a viral etiology for SHT.
Ultrastructurally, in the liver, virions are noted only within hepatocytes and in the space of Disse and not within the endothelium. This suggests tropism of the SHT virus for the epithelial but not endothelial cell population in the liver.
When clearly visible, 60-100nm round virions with a trilaminar capsid can be seen to contain up to 7 electron-dense aggregates.
- Del-Pozo, J., Mishra, N., Kabuusu, R., Cheetham, S., Eldar, A., Bacharach, E., … & Ferguson, H. W. (2017). Syncytial hepatitis of tilapia (Oreochromis niloticus L.) is associated with orthomyxovirus-like virions in hepatocytes. Veterinary pathology, 54(1), 164-170.
- Ferguson, H. W., Kabuusu, R., Beltran, S., Reyes, E., Lince, J. A., & Del Pozo, J. (2014). Syncytial hepatitis of farmed tilapia, Oreochromis niloticus (L.): a case report. J Fish Dis, 37(6), 583-589.